In order to enhance a shape retaining property of a gasket consisting only of a rubber, prevent damage to a casing for an electronic equipment due to high reactive force of the gasket, and make assembling of the casing easy, a seal structure comprises a gasket installed in a non-adhesion manner between a case and a lid to be interposed in a compressed state when the case and the lid are assembled, and a resin film integrated with the gasket to enhance the shape retaining property of the gasket, the gasket has a portion compressed between the case and the lid when they are assembled, and a portion not compressed between them when assembled and the resin film is integrated with the portion which is not compressed.